COAL ACID MINE DRAINAGE TREATMENT USING CEMENT KILN DUST

摘要

Sulphurs are present in different rocks. During mining activities and the sulphur removal processes Acid Mine Drainage (AMD) may beproduced, by sulphate ions (SO42-) in solution. AMDs are the main source of pollution from mining operations and in Colombia theirdischarge into natural bodies of water must comply with national environmental regulations (pH between 5 and 9). Cement Kiln Dust(CKD), with calcium carbonate as its main component, from a Cementos Argos S.A. plant was used to neutralize an AMD generatedthrough a coal bio-desulphurization process. Neutralized AMDs had pH values between 7.72 ? 8.05 and the sulphates removal rangedfrom 67% to 70%. Precipitated sludge was dried and analyzed in order to determine its chemical and mineralogical composition.Moisture content was between 69% and 81%; this precipitated material was composed of gypsum with approximately 50% purity, aswell as calcium carbonate. This composition makes it suitable for use in cement production.